Original Prusa MK4S vs Bambu Lab P1S: specs side by side

The Original Prusa MK4S is an open-frame bedslinger (its bed moves front to back) with a 250 × 210 × 220 mm build volume and open-source firmware. The Bambu Lab P1S is an enclosed CoreXY printer (its toolhead moves in X and Y) with a 256 × 256 × 256 mm build volume and proprietary firmware. The MK4S launched at $1,099 and the P1S at $699.

How are the Original Prusa MK4S and Bambu Lab P1S built differently?

The Original Prusa MK4S has an open frame and a bed that carries the part along the Y axis. The Bambu Lab P1S moves its toolhead on CoreXY belts inside an enclosure, and its bed moves only in Z. So the MK4S moves the part back and forth during printing, while the P1S only lowers it layer by layer.

An open frame gives direct access to the printer. An enclosure holds heat around the part and contains fumes. The motion systems guide covers how each layout behaves.

Which one has the larger build volume?

The Bambu Lab P1S has the larger build volume: 256 × 256 × 256 mm, about 16.8 liters. The Original Prusa MK4S lists 250 × 210 × 220 mm, about 11.6 liters, so the P1S holds about 45% more. The P1S is larger on every axis, with the biggest gap on Y (256 mm versus 210 mm).

How do the temperatures and nozzles compare?

The Bambu Lab P1S lists the hotter hotend and the Original Prusa MK4S the hotter bed. The MK4S lists 290 °C at the hotend and 120 °C at the bed, with a brass 0.4 mm nozzle. The P1S lists 300 °C and 100 °C, with a stainless steel 0.4 mm nozzle. Neither maker states a chamber temperature.

The MK4S has an open frame, so it has no chamber to heat.

What do the makers say about speed?

Only one of the two makers publishes speed figures. Bambu Lab lists a 500 mm/s maximum speed, 20,000 mm/s² acceleration and 32 mm³/s flow for the Bambu Lab P1S. Prusa Research publishes no maximum speed, acceleration or flow figure for the Original Prusa MK4S, so the spec sheets alone cannot compare the two on speed.

A dash in the table means no published figure, not a slow printer.

What is different about the firmware?

The Original Prusa MK4S runs Prusa Firmware Buddy, which Prusa Research publishes on GitHub as open source under the GPL-3.0 license. The Bambu Lab P1S runs Bambu Lab’s proprietary firmware. The firmware guide explains what open source changes in practice.

Connectivity differs too. The MK4S lists Ethernet alongside Wi-Fi; the P1S lists Wi-Fi, Bluetooth and an SD card.